The number on your smartwatch you should pay most attention to

How can you find out your VO2 max?

Completing a VO2 max test in a lab is the gold-standard option.

Jonathan Robinson, an applied sport scientist at the University of Bath, conducts these tests on Olympic athletes and professional footballers, as well as the health-conscious who want to find out their reading.

It involves exercising, usually running or cycling, at increasing levels of intensity until a person can’t keep going – a point typically hit about 10 minutes in. While doing this, Mr Robinson and his team measure the concentrations of oxygen and carbon dioxide that participants breathe in and out to calculate their VO2 max.

Mr Robinson says members of the public are increasingly coming forward to get tested ahead as part of their training regime for marathons, triathlons and cycling events. For this group, the ideal is to get VO2 max checked at the start of their training and a follow-up a few months later to see how it has changed.

“Do the second test early enough that you’ve got enough time prior to your event to make any more changes that you need to make,” he recommends.

Others are interested in the links between VO2 max and longevity and just want to know what their score is and log it over time, he adds.

“If you’re just doing it to monitor your health and wellbeing, you could get tested at any point really,” Mr Robinson says. “Then obviously, the idea is that you come back and retest it – annually or up to twice a year. But obviously, it depends on people’s plans and budgets.”

At his Sport Science Lab the test costs £135 ($256), which he says is at the cheaper end of the scale. Some labs charge up to £250, according to Mr Robinson.

For those reluctant to fork out this sum, their smartwatch can provide a decent guide. Instead of measuring oxygen levels, the devices provide a VO2 max estimate based on pace and heart rate. Garmin users can find their VO2 max data under the “health and performance” tab on the app, or it flashes up on the watch after exercise. Those with an Apple Watch can find their data on the “cardio fitness” section of the Health app.

“They’re quite accurate at the moment,” Mr Robinson says. “If you asked me five years ago, I would have said that they’re OK as a guide, but they’re not really particularly close, whereas now they’re much closer. If you’ve got a VO2 max of 55, people’s watches might say 50 to 57 – a little bit higher or lower. Very occasionally, I’ll get one which is off.”

However, Gray is more sceptical. “The consensus is they are highly variable and not a good replacement for direct measurement in the lab,” he says. “They rely on several assumptions such as someone’s maximal heart rate, the HR-work rate and HR-VO2 relationship, in which there is a high level of variability that then comes into the calculations.

“For example, in the lab, my VO2 max is around 45 but my Garmin says 58 – I would love to believe my Garmin.”

The traditional beep test can also provide a guide to VO2 max levels. “Many years ago, hundreds of people were put through the VO2 max tests in the lab, then did the beep test – a fitness test that gets progressively faster – and the results were correlated into a table that people can read their results from as a bit of a guide,” Mr Robinson says.

There’s also the Cooper Test – you run as far as you can in 12 minutes and that can be equated to a VO2 max score – and the Rockport Walk Test, which matches up the time taken to walk one mile to a score, he says.

How does VO2 max influence your fitness and health?

VO2 max acts as a proxy of our physical fitness. “Our ability to take up and use large volumes of oxygen means we have the capacity to perform exercise at a higher intensity,” Gray explains.

“So it is very important for endurance exercise performance. It is not the only factor though, and things like how efficiently we use that oxygen are also very important.”

The metric can also reflect the state of your health. Research from Gray and his colleagues, published in the British Journal of Sports Medicine, revealed that those with better scores were more likely to live longer and faced a lower risk from cardiovascular disease, respiratory disease and colorectal cancer.

“It is also a good predictor of how well people will cope with major surgery, and their prognosis after,” he says. “Often if VO2 max is too low people will not be given the surgery.”

How can you improve your VO2 max?

Any aerobic exercise – those that get the heart pumping – can improve VO2 max scores.

This can be anything from a low intensity longer duration workout, such as cycling or running at 70 per cent of your maximum effort at least four times a week, to higher intensity interval exercise, which typically involves four minutes of maximum effort followed by four minutes of low effort, completed four times in a row, Gray suggests.

“Really whatever form of aerobic exercise you prefer – you might get a little bit of a gain from some strength training too,” he says.

“However, there are some things we can’t change that affect VO2 max, such as our sex and our genetics – we inherit about 50 per cent of our VO2 max ability.”

The Telegraph London